System and method for controlling work machine

ABSTRACT

A system controls a work machine that loads materials onto a conveyance vehicle. The system includes a controller and a detection device. The controller controls the work machine in an automatic control mode in which work is performed automatically. The detection device detects an approach of the conveyance vehicle toward the work machine. The automatic control mode includes a loading mode in which the work machine is caused to move to perform loading work for loading onto the conveyance vehicle, and an other mode other than the loading mode. The other mode includes at least one of a mode for gathering fallen materials and a digging mode for further increasing the materials by digging. The controller causes the automatic control mode to transition from the other mode to the loading mode when the approach of the conveyance vehicle is detected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National stage application of InternationalApplication No. PCT/JP2019/010889, filed on Mar. 15, 2019. This U.S.National stage application claims priority under 35 U.S.C. § 119(a) toJapanese Patent Application No. 2018-144228, filed in Japan on Jul. 31,2018, the entire contents of which are hereby incorporated herein byreference.

BACKGROUND Field of the Invention

The present invention relates to a system and a method for controlling awork machine.

Background Information

There is work which involves digging materials such as soil and the likeby a work machine such as a hydraulic excavator and loading thematerials onto a conveyance vehicle such as a dump truck. The conveyancevehicle is loaded with the materials at a predetermined loadingposition. The conveyance vehicle travels to a predetermined dumpingposition and dumps the materials at the dumping position. The conveyancevehicle then returns to the loading position and materials are loadedagain by the work machine onto the conveyance vehicle.

Conventionally, a technique for performing the above loading work by thework machine with automatic control is known. For example, JapanesePatent Laid-Open No. 2000-192514 indicates that the digging position andthe unloading position are previously learned by a controller of thework machine. The controller controls the work machine so as to performdigging at the digging position, cause the work machine to rotate fromthe digging position to the unloading position, and unload materials atthe unloading position.

SUMMARY

According to the above technique, the loading work can be performed bythe work machine with automatic control. However, the loading work isperformed not only by the work machine but also in cooperation with theconveyance vehicle. Therefore, it is important to perform the work whilesuitably coordinating the work machine and the conveyance vehicle inorder to efficiently perform the loading work.

An object of the present invention is to perform loading work by thework machine with automatic control and suitably coordinate the workmachine and the conveyance vehicle.

A system according to a first aspect is a system for controlling a workmachine that loads materials onto a conveyance vehicle. The systemaccording to the present aspect includes a controller and a detectiondevice. The controller controls the work machine in an automatic controlmode in which work is performed automatically. The detection devicedetects an approach of the conveyance vehicle toward the work machine.The automatic control mode includes a loading mode and a mode other thanthe loading mode. In the loading mode, the controller causes the workmachine to operate so as to perform loading work for loading onto theconveyance vehicle. The other mode includes at least one of a mode forgathering fallen materials and a digging mode for further increasing thematerials by digging. The controller causes the automatic control modeto transition from another mode to the loading mode when the approach ofthe conveyance vehicle has been detected.

A method according to a second aspect is a method for controlling a workmachine that loads materials onto a conveyance vehicle. The methodincludes detecting an approach of the conveyance vehicle toward the workmachine, and controlling the work machine in an automatic control modein which work is performed automatically. The automatic control modeincludes a loading mode in which the work machine is caused to move toperform loading work for loading onto the conveyance vehicle, and another mode other than the loading mode. The other mode includes at leastone of a mode for gathering fallen materials and a digging mode forfurther increasing the materials by digging. The controlling the workmachine includes causing the automatic control mode to transition fromthe other mode to the loading mode when the approach of the conveyancevehicle is detected.

According to the present invention, work can be performed by suitablycoordinating the work machine and the conveyance vehicle. Consequently,the loading work by the work machine is performed with the automaticcontrol and work efficiency can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view illustrating an example of a work site where awork machine is used.

FIG. 2 is a side view of the work machine.

FIG. 3 is a block diagram illustrating a configuration of the workmachine.

FIG. 4 is a side view of a conveyance vehicle.

FIG. 5 is a block diagram illustrating a configuration of the conveyancevehicle.

FIG. 6 is a flowchart illustrating processes in a standby mode.

FIG. 7 is a flowchart illustrating processes in a loading mode.

FIG. 8 is a flowchart illustrating processes in the loading mode.

FIG. 9 is a flowchart illustrating processes in the in loading mode.

FIG. 10 is a plan view schematically illustrating conditions of the worksite during an automatic control mode.

FIG. 11 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 12 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 13 a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 14 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 15 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 16 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 17 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 18 is a plan view schematically illustrating conditions of the worksite during the automatic control mode.

FIG. 19 is a view illustrating an example of an image captured by afirst camera or a second camera.

FIG. 20 is a view illustrating an example of an image captured by thefirst camera.

FIG. 21 is a diagram illustrating the extent of materials that can bedug by the work machine at the current position.

FIG. 22 is a diagram illustrating an example of a cross section of thecurrent topography and a digging path.

FIG. 23 is a view illustrating an example of an image captured by thefirst camera.

DETAILED DESCRIPTION OF EMBODIMENT(S)

A control system of a work machine 1 according to an embodiment will nowbe described with reference to the drawings. FIG. 1 is a plan viewillustrating an example of a work site where the work machine 1 is used.The work machine 1 and a conveyance vehicle 2 are disposed at the worksite. The work machine 1 performs work in cooperation with theconveyance vehicle 2 with automatic control.

In the present embodiment, the work machine 1 is a hydraulic excavator.The conveyance vehicle 2 is a dump truck. The work machine 1 is disposedbeside a predetermined digging position L1 in the work site. Theconveyance vehicle 2 travels back and forth between a predeterminedloading position L2 and a predetermined dumping position L3 in the worksite. The work machine 1 digs the digging position L1 with automaticcontrol and loads materials such as soil and the like as a target to bedug onto the conveyance vehicle 2 that is stopped at the loadingposition L2. The conveyance vehicle 2 loaded with the materials travelsto the dumping position L3 and unloads the materials at the dumpingposition L3. Another work machine 3 such as a bulldozer is disposed atthe dumping position L3 and spreads the materials unloaded at thedumping position L3. The conveyance vehicle 2 that has unloaded thematerials travels to the loading position L2 and the work machine 1loads again the materials onto the conveyance vehicle 2 that is stoppedat the loading position L2. The materials of the digging position L1 aretransported to the dumping position L3 by repeating the above work.

FIG. 2 is a side view of the work machine 1. As illustrated in FIG. 2,the work machine 1 includes a vehicle body 11 and a work implement 12.The vehicle body 11 includes a rotating body 13 and a traveling body 14.The rotating body 13 is rotatably attached to the traveling body 14. Acab 15 is disposed on the rotating body 13. However, the cab 15 may beomitted. The traveling body 14 includes crawler belts 16. The crawlerbelts 16 are driven by driving force from an engine 24 described later,whereby the work machine 1 travels.

The work implement 12 is attached to the front part of the vehicle body11. The work implement 12 includes a boom 17, an arm 18, and a bucket19. The boom 17 is attached to the rotating body 13 so as to allowmovement in the up and down direction. The arm 18 is movably attached tothe boom 17. The bucket 19 is movably attached to the arm 18. The workimplement 12 includes a boom cylinder 21, an arm cylinder 22, and abucket cylinder 23. The boom cylinder 21, the arm cylinder 22, and thebucket cylinder 23 are hydraulic cylinders and are driven by hydraulicfluid from a hydraulic pump 25 described later. The boom cylinder 21actuates the boom 17. The arm cylinder 22 actuates the arm 18. Thebucket cylinder 23 actuates the bucket 19.

FIG. 3 is a block diagram illustrating a configuration of a controlsystem of the work machine 1. As illustrated in FIG. 3, the work machine1 includes an engine 24, a hydraulic pump 25, a power transmissiondevice 26, and a controller 27.

The engine 24 is controlled by command signals from the controller 27.The hydraulic pump 25 is driven by the engine 24 to discharge hydraulicfluid. The hydraulic fluid discharged from the hydraulic pump 25 issupplied to the boom cylinder 21, the arm cylinder 22, and the bucketcylinder 23.

The work machine 1 includes a rotation motor 28. The rotation motor 28is a hydraulic motor and is driven by hydraulic fluid from the hydraulicpump 25. The rotation motor 28 rotates the rotating body 13. While onlyone hydraulic pump 25 is illustrated in FIG. 2, a plurality of hydraulicpumps may be provided.

A pump control device 29 is connected to the hydraulic pump 25. Thehydraulic pump 25 is a variable displacement pump. The pump controldevice 29 controls the inclination angle of the hydraulic pump 25. Thepump control device 29 includes, for example, an electromagnetic valveand is controlled by command signals from the controller 27. Thecontroller 27 controls the displacement of the hydraulic pump 25 bycontrolling the pump control device 29.

The hydraulic pump 25, the cylinders 21 to 23, and the rotation motor 28are connected to each other by means of a hydraulic circuit via acontrol valve 31. The control valve 31 is controlled by command signalsfrom the controller 27. The control valve 31 controls the flow rate ofthe hydraulic fluid supplied from the hydraulic pump 25 to the cylinders21 to 23 and the rotation motor 28. The controller 27 controls theoperation of the work implement 12 by controlling the control valve 31.The controller 27 also controls the rotation of the rotating body 13 bycontrolling the control valve 31.

The power transmission device 26 transmits driving force from the engine24 to the traveling body 14. The power transmission device 26 may be,for example, a torque converter or a transmission having a plurality oftransmission gears. Alternatively, the power transmission device 26 maybe another type of transmission such as a hydro static transmission(HST) or a hydraulic mechanical transmission (HMT).

The controller 27 is programmed so as to control the work machine 1based on acquired data. The controller 27 causes the work machine 1 totravel by controlling the engine 24, the traveling body 14, and thepower transmission device 26. The controller 27 causes the workimplement 12 to operate by controlling the engine 24, the hydraulic pump25, and the control valve 31.

The controller 27 includes a processor 271 such as a CPU or GPU, and astorage device 272. The processor 271 performs processing for theautomatic control of the work machine 1. The storage device 272 includesa memory such as RAM or a ROM, and an auxiliary storage device such as ahard disk drive (HDD) or a solid state drive (SSD). The storage device272 stores data and programs for the automatic control of the workmachine 1.

The work machine 1 includes load sensors 32 a to 32 c. The load sensors32 a to 32 c detect a load applied to the work implement 12 and outputload data indicative of the load. In the present embodiment, the loadsensors 32 a to 32 c are hydraulic pressure sensors and detect thehydraulic pressures of the cylinders 21 to 23, respectively. The loaddata indicates the hydraulic pressures of the cylinders 21 to 23. Thecontroller 27 is communicably connected to the load sensors 32 a to 32 cby wire or wirelessly. The controller 27 receives the load data from theload sensors 32 a to 32 c.

The work machine 1 includes a position sensor 33, work implement sensors34 a to 34 c, and a rotation angle sensor 39. The position sensor 33detects the position of the work machine 1 and outputs position dataindicative of the position of the work machine 1. The position sensor 33includes a global navigation satellite system (GNSS) receiver and aninertial measurement unit (IMU). The GNSS receiver is, for example, areceiver for a global positioning system (GPS). The position dataincludes data indicative of the position of the work machine 1 output bythe GNSS receiver and data indicative of the attitude of the vehiclebody 11 output by the IMU. The attitude of the vehicle body 11 includesan angle (pitch angle) with respect to the horizontal in thelongitudinal direction of the work machine 1 and an angle (roll angle)with respect to the horizontal in the lateral direction of the workmachine 1.

The work implement sensors 34 a to 34 c detect the attitude of the workimplement 12 and output attitude data indicative of the attitude of thework implement 12. The work implement sensors 34 a to 34 c are, forexample, stroke sensors that detect the stroke amounts of the cylinders21 to 23. The attitude data of the work implement 12 includes the strokeamounts of the cylinders 21 to 23. Alternatively, the work implementsensors 34 a to 34 c may be other sensors such as sensors that detectthe rotation angles of the boom 17, the arm 18, and the bucket 19,respectively. The rotation angle sensor 39 detects the rotation angle ofthe rotating body 13 with respect to the traveling body 14 and outputsrotation angle data indicative of the rotation angle.

The controller 27 is communicably connected to the position sensor 33,the work implement sensors 34 a to 34 c, and the rotation angle sensor39 by wire or wirelessly. The controller 27 receives the position dataof the work machine 1, the attitude data of the work implement 12, andthe rotation angle data from the position sensor 33, the work implementsensors 34 a to 34 c, and the rotation angle sensor 39, respectively.The controller 27 calculates the blade tip position of the bucket 19from the position data, the attitude data, and the rotation angle data.For example, the position data of the work machine 1 indicates theglobal coordinates of the position sensor 33. The controller 27calculates the global coordinates of the blade tip position of thebucket 19 from the global coordinates of the position sensor 33 based onthe attitude data of the work implement 12 and the rotation angle data.

The work machine 1 includes a topography sensor 35. The topographysensor 35 measures a topography in a periphery of the work machine 1 andoutputs topography data indicative of the topography measured by thetopography sensor 35. In the present embodiment, the topography sensor35 is attached to a side part of the rotating body 13. The topographysensor 35 measures the topography located to the side of the rotatingbody 13. The topography sensor 35 is, for example, a laser imagingdetection and ranging (LIDAR) device. The LIDAR device measures thedistances to a plurality of measurement points on the topography byirradiating a laser and measuring the reflected light thereof. Thetopography data indicates the positions of the measurement points withrespect to the work machine 1.

The work machine 1 includes a first camera 36 and a plurality of secondcameras 37. The first camera 36 faces forward from the rotating body 13and is attached to the rotating body 13. The first camera 36 capturestoward the front of the rotating body 13. The first camera 36 is astereo camera. The first camera 36 outputs first image data indicativeof captured moving images.

The plurality of second cameras 37 are attached to the rotating body 13and facing left, right, and rear from the rotating body 13. The secondcameras 37 output second image data indicative of captured movingimages. The second cameras 37 may be single-lens cameras. Alternatively,the second cameras 37 may be stereo cameras in the same way as the firstcamera 36. The controller 27 is communicably connected to the firstcamera 36 and the second cameras 37 by wire or wirelessly. Thecontroller 27 receives the first image data from the first camera 36.The controller 27 receives the second image data from the second cameras37.

The work machine 1 includes a communication device 38. The communicationdevice 38 performs data communication with a device outside the workmachine 1. The communication device 38 performs data communication witha remote computer apparatus 4 outside the work machine 1. The remotecomputer apparatus 4 may be disposed at the work site. Alternatively,the remote computer apparatus 4 may be disposed at a management centerremote from the work site. The remote computer apparatus 4 includes adisplay 401 and an input device 402.

The display 401 displays images related to the work machine 1. Thedisplay 401 displays images corresponding to signals received from thecontroller 27 via the communication device 38. The input device 402 isoperated by an operator. The input device 402 may include, for example,a touch screen or may include hardware keys. The remote computerapparatus 4 transmits signals indicative of commands input by the inputdevice 402, to the controller 27 via the communication device 38. Thecommunication device 38 performs data communication with the conveyancevehicle 2.

FIG. 4 is a side view of the conveyance vehicle 2. As illustrated inFIG. 4, the conveyance vehicle 2 includes a vehicle body 51, a travelingbody 52, and a bed 53. The vehicle body 51 is supported by the travelingbody 52. The traveling body 52 includes crawler belts 54. The crawlerbelts 54 are driven by the driving force from an engine 55 describedlater, whereby the conveyance vehicle 2 travels. The bed 53 is supportedby the vehicle body 51. The bed 53 is configured to move between adumping attitude and a conveying attitude. In FIG. 4, the bed 53indicated by a solid line indicates the position of the bed 53 in theconveying attitude. The bed 53 indicated by a chain double-dashed lineindicates the position of the bed 53 in the dumping attitude. In theconveying attitude, the bed 53 is disposed approximately horizontally.In the dumping attitude, the bed 53 is inclined with respect to theconveying attitude.

FIG. 5 is a block diagram illustrating a configuration of a controlsystem of the conveyance vehicle 2. The conveyance vehicle 2 includes anengine 55, a hydraulic pump 56, a power transmission device 57, a liftcylinder 58, a rotation motor 59, a controller 61, and a control valve62. The controller 61 includes a processor 611, a volatile storage unit612, and a non-volatile storage unit 613.

The engine 55, the hydraulic pump 56, the power transmission device 57,the controller 61, and the control valve 62 have the same configurationsas the engine 24, the hydraulic pump 25, the power transmission device26, the controller 27, and the control valve 31 of the work machine 1,respectively. Therefore, detailed explanations thereof are omitted.

The lift cylinder 58 is a hydraulic cylinder. The rotation motor 59 is ahydraulic motor. The hydraulic fluid discharged from the hydraulic pump56 is supplied to the lift cylinder 58 and the rotation motor 59. Thelift cylinder 58 and the rotation motor 59 are driven by hydraulic fluidfrom the hydraulic pump 56. The lift cylinder 58 raises and lowers thebed 53. Consequently, the attitude of the bed 53 is switched between theconveying attitude and the dumping attitude. The rotation motor 59causes the vehicle body 51 to rotate with respect to the traveling body52. The controller 61 controls the lift cylinder 58 by means of thecontrol valve 62 thereby controlling the operation of the bed 53. Inaddition, the controller 61 controls the rotation motor 59 by means ofthe control valve 62 thereby controlling the rotation of the vehiclebody 51.

The conveyance vehicle 2 includes a position sensor 63, a bed sensor 64,and a rotation angle sensor 65. The position sensor 63 outputs positiondata in the same way as the position sensor 33 of the work machine 1.The position data includes data indicative of the position of theconveyance vehicle 2 and data indicative of the attitude of the vehiclebody 51.

The bed sensor 64 detects the attitude of the bed 53 and outputs beddata indicative of the attitude of the bed 53. The bed sensor 64 is, forexample, a stroke sensor that detects the stroke amount of the liftcylinder 58. The bed data includes the stroke amount of the liftcylinder 58. Alternatively, the bed sensor 64 may be another type ofsensor such as a sensor that detects the inclination angle of the bed53. The rotation angle sensor 65 detects the rotation angle of thevehicle body 51 with respect to the traveling body 52 and outputsrotation angle data indicative of the rotation angle.

The controller 61 is communicably connected to the position sensor 63,the bed sensor 64, the rotation angle sensor 65 by wire or wirelessly.The controller 61 receives the position data, the bed data, and therotation angle data from the position sensor 63, the bed sensor 64, andthe rotation angle sensor 65, respectively.

The conveyance vehicle 2 includes a communication device 66. Thecontroller 61 of the conveyance vehicle 2 performs data communicationwith the controller 27 of the work machine 1 via the communicationdevice 66. The controller 61 of the conveyance vehicle 2 transmits theposition data, the bed data, and the rotation angle data of theconveyance vehicle 2 via the communication device 66. The controller 27of the work machine 1 receives the position data, the bed data, and therotation angle data of the conveyance vehicle 2 via the communicationdevice 38. The controller 27 of the work machine 1 stores vehicledimension data indicative of the dispositions and the dimensions of thevehicle body 51 and the bed 53 of the conveyance vehicle 2. Thecontroller 27 calculates the position of the bed 53 from the positiondata, the bed data, the rotation angle data, and the vehicle dimensiondata of the conveyance vehicle 2.

Next, the processing of the automatic control mode executed by thecontroller 27 of the work machine 1 will be described. In the automaticcontrol mode, the controller 27 controls the work machine 1 so that theabovementioned digging and loading work is performed automatically.FIGS. 6 to 9 are flowcharts illustrating the processing of the automaticcontrol mode.

The automatic control mode includes a loading mode and modes other thanthe loading mode. Another mode in the present embodiment is a standbymode. In the standby mode, the controller 27 causes the work machine 1to wait on standby until the conveyance vehicle 2 has arrived at theloading position L2 and stopped. In addition to the standby mode, theother modes may include modes such as a mode for gathering fallenmaterials, a digging mode for digging another region and furtherincreasing the materials, or the like.

In the loading mode, the controller 27 causes the work machine 1 tooperate so as to perform loading work onto the conveyance vehicle 2 whenthe conveyance vehicle 2 is stopped at the loading position L2. FIG. 6is a flowchart illustrating processes in the standby mode. FIGS. 7 to 9are flowcharts illustrating processes in the loading mode. FIGS. 10 to18 are plan views schematically illustrating conditions of the work siteduring the automatic control mode.

When receiving a starting command of the automatic control mode, thecontroller 27 starts the engine 24 of the work machine 1 and executesthe processes of the standby mode illustrated in FIG. 6. As illustratedin FIG. 10, the starting command of the automatic control mode is outputfrom the abovementioned remote computer apparatus 4 due to, for example,the operator operating the input device 402 of the remote computerapparatus 4. The controller 27 receives the starting command through thecommunication device 38. In addition, the conveyance vehicle 2 alsoreceives the starting command of the automatic control mode. Uponreceiving the starting command of the automatic control mode, theconveyance vehicle 2 starts moving toward the loading position L2.

As illustrated in FIG. 6, in step S101, the controller 27 causes thework machine 1 to wait on standby in a waiting attitude for unloading.That is, in the standby mode, the controller 27 maintains the workimplement 12, the rotating body 13, and the traveling body 14 in thewaiting attitude for unloading. As illustrated in FIG. 10, in thewaiting attitude for unloading, the work implement 12 is disposed so asto face the loading position L2. That is, in the waiting attitude forunloading, the front of the rotating body 13 faces the loading positionL2. In addition, in the waiting attitude for unloading, the bucket 19 isdisposed in a position higher than the height of the bed 53 of theconveyance vehicle 2.

In step S102, the controller 27 acquires the position of the workmachine 1. Here, the controller 27 acquires the position data of thework machine 1, the attitude data of the work implement 12, and therotation angle data from the position sensor 33, the work implementsensors 34 a to 34 c, and the rotation angle sensor 39, respectively.The controller 27 calculates the blade tip position of the bucket 19from the position data, the attitude data, and the rotation angle data.

In step S103, the controller 27 acquires image data. Here, thecontroller 27 acquires the first image data indicative of moving imagesin front of the rotating body 13 from the first camera 36. Thecontroller 27 acquires the second image data indicative of moving imagesto the both sides and to the rear side from the rotating body 13, fromthe second cameras 37. The first camera 36 and the second cameras 37constantly capture images to generate the first image data and thesecond image data at least during the execution of the automatic controlmode. The controller 27 acquires the first image data and the secondimage data in real time from the first camera 36 and the second cameras37 at least during the execution of the automatic control mode.

In step S104, the controller 27 executes image processing 1. The imageprocessing 1 detects the presence of a person in the periphery of thework machine 1 with image recognition technology based on the firstimage data and the second image data. Therefore, the first camera 36 andthe second cameras 37 correspond to a person detection device thatdetects the presence of a person in a region in the periphery of thework machine 1.

The controller 27 detects the presence of a person in the imagesindicated by the first image data and the second image data by using,for example, image recognition technology that uses artificialintelligence (AI). FIG. 19 is a view illustrating an example of an imagecaptured by the first camera 36 or the second cameras 37. As illustratedin FIG. 19, when a person is included in the images indicated by thefirst image data or the second image data, the controller 27 recognizesand detects a person in the images. In step S105, the controller 27determines whether the presence of a person in the periphery of the wokmachine 1 is detected. When the presence of a person is not detected,the processing proceeds to step S106.

In step S106, the controller 27 executes image processing 2. In theimage processing 2, the controller 27 detects the presence of theconveyance vehicle 2 with the image recognition technology based on thefirst image data. Therefore, the first camera 36 corresponds to avehicle detection device that detects an approach of the conveyancevehicle 2 toward the work machine 1. The image recognition technology isthe same as in step S104. As illustrated in FIG. 11, the controller 27detects the presence of the conveyance vehicle 2 when the conveyancevehicle 2 has reached the image capturing range of the first camera 36.

FIG. 20 is a view illustrating an example of an image captured by thefirst camera 36 when the conveyance vehicle 2 has reached the imagecapturing range of the first camera 36. As illustrated in FIG. 20, whenthe conveyance vehicle 2 is included in the images indicated by thefirst image data, the controller 27 recognizes and detects theconveyance vehicle 2 in the images.

In step S107, the controller 27 communicates with the conveyance vehicle2. Here, the controller 27 receives the position data of the conveyancevehicle 2 from the conveyance vehicle 2 via the communication device 38.The controller 27 also receives the bed data and the rotation angle datafrom the conveyance vehicle 2 via the communication device 38.

In step S108, the controller 27 determines whether the approach of theconveyance vehicle 2 is detected. The controller 27 determines that theapproach of the conveyance vehicle 2 is detected when the distance fromthe work machine 1 to the conveyance vehicle 2 is equal to or less thana predetermined threshold. The controller 27 calculates the distancefrom the work machine 1 to the conveyance vehicle 2 by analyzing thefirst image data. Alternatively, the controller 27 may calculate thedistance from the work machine 1 to the conveyance vehicle 2 from theposition data of the work machine 1 and the position data of theconveyance vehicle 2. When the approach of the conveyance vehicle 2 isdetected, the processing proceeds to step S201 illustrated in FIG. 7.That is, the controller 27 causes the automatic control mode totransition from the standby mode to the loading mode.

The fact that no person is detected in step S105 and the fact that theapproach of the conveyance vehicle 2 is detected in step S108 representthe transition condition for causing the automatic control mode totransition from the standby mode to the loading mode. The controller 27causes the automatic control mode to transition from the standby mode tothe loading mode when the transition condition is satisfied. Thecontroller 27 does not cause the automatic control mode to transitionfrom the standby mode to the loading mode and maintains the standby modewhen the transition condition is not satisfied. The transition conditionmay also include other conditions.

When the controller 27 does not detect the approach of the conveyancevehicle 2 in step S108, the processing proceeds to step S109. In stepS109, the controller 27 determines whether a finishing signal isreceived. The finishing signal is transmitted from the remote computerapparatus 4. The finishing signal is transmitted from the remotecomputer apparatus 4 to the controller 27 due to the operator operatingthe input device 402. Upon receiving the finishing signal, thecontroller 27 finishes the automatic control mode. When the automaticcontrol mode is finished, the controller 27 stops the engine 24 of thework machine 1. In addition, the controller 61 of the conveyance vehicle2 stops the conveyance vehicle 2 upon receiving the finishing signal.

As illustrated in FIG. 12, when a person 100 has intruded into theperiphery of the work machine 1, the controller 27 detects the presenceof the person 100 in step S105. When the controller 27 detects thepresence of the person 100, the processing proceeds to step S110. Instep S110, the controller 27 outputs a warning signal so as to cause anoutput device to output a warning. In the present embodiment, the outputdevice is the remote computer apparatus 4. Upon receiving the warningsignal, the remote computer apparatus 4 displays a message or an imageindicative of the warning on the display 401. The remote computerapparatus 4 may output a sound which represents the warning uponreceiving the warning signal.

The output device is not limited to the remote computer apparatus 4 andmay be another device. For example, the output device may be a warninglamp or a loudspeaker attached to the work machine 1 or disposed on theoutside of the work machine 1. The controller 27 may output a commandsignal so as to illuminate the warning lamp or emit a warning sound fromthe loudspeaker when the presence of a person is detected.

The controller 27 determines whether the finishing signal is received instep S109 after causing the output device to output the warning signalin step S110. When the finishing signal is received, the controller 27stops the automatic control mode. When the finishing signal is notreceived, the controller 27 maintains the automatic control mode in thestandby mode.

When detecting the presence of a person in the periphery of the workmachine 1 in the standby mode, the controller 27 does not transition theautomatic control mode to the loading mode and maintains the standbymode even when detecting the approach of the conveyance vehicle 2. Whendetecting the presence of a person during the loading mode describedlater, the controller 27 stops the operations of the work implement 12and the rotating body 13. In addition, when detecting the presence of aperson, the controller 27 may transmit a command signal to stop theconveyance vehicle 2 to the controller 61 of the conveyance vehicle 2 ineither of the standby mode or the loading mode.

Next, the processing in the loading mode will be explained. In theloading mode, the controller 27 performs digging by the work implement12 at the predetermined digging position L1, causes the work implement12 to rotate with the rotating body 13 from the digging position L1toward the loading position L2, and unloads the materials from the workimplement 12 at the loading position L2 to perform the loading work.

As illustrated in FIG. 7, in the loading mode, the controller 27measures a topography in step S201. Here, as illustrated in FIG. 13, thetopography sensor 35 measures the topography of the digging position L1located on a side of the work machine 1. The controller 27 acquirestopography data indicative of the topography of the digging position L1measured by the topography sensor 35. The controller 27 determineswhether the rotating body 13 is stopped or operating, and whendetermining that the rotating body 13 is stopped, the controller 27 maymeasure the topography by the topography sensor 35.

In step S202, the controller 27 determines whether the digging amountcan be secured. Here, the controller 27 determines whether the materialsof a predetermined amount or more can be acquired by digging when thework implement 12 and the rotating body 13 are operated at the currentposition of the work machine 1. For example, as illustrated in FIG. 21,the controller 27 calculates the amount of the materials that can be dugat the current position from the trajectory of the work implement 12when the work implement 12 and the rotating body 13 are operated at thecurrent position of the work machine 1 and from the topography of thedigging position L1 indicated by the topography data. In FIG. 21,hatching is applied to the extent that can be dug when the workimplement 12 is operated. The controller 27 determines that the diggingamount can be secured when the amount of the materials that can be dugis equal to or greater than a predetermined threshold. When thecontroller 27 determines that the digging amount cannot be secured, theprocessing proceeds to step S203.

In step S203, the controller 27 adjusts the position of the work machine1. For example, the controller 27 causes the work machine 1 to moveforward or backward a predetermined distance. Then, the controller 27measures the topography again in step S201 and determines whether thedigging amount can be secured in step S202.

When the controller 27 determines that the digging amount can be securedin step S202, the processing proceeds to step S204. In step S204, thecontroller 27 calculates a possible loading weight. The controller 27stores the maximum loading weight that can be loaded onto the conveyancevehicle 2. The controller 27 calculates the possible loading weight fromthe maximum loading weight and the weight of the materials alreadyloaded onto the conveyance vehicle 2.

In step S205, the controller 27 establishes a digging plan. Here, thecontroller 27 determines a digging path PA1 (in FIG. 22) and a targetrotation angle TA1 (in FIG. 14) from the current position of the workmachine 1, the topography data, and a target volume. The digging pathPA1 is a target trajectory of the blade tip of the work implement 12.The controller 27 determines the digging path PA1 from the currentposition of the work machine 1 and the topography data so that theamount of the materials to be dug by the work implement 12 matches thetarget volume.

As described later, the controller 27 is able to calculate the weight ofthe materials held in the bucket 19 by digging. The controller 27accumulates the weight of the materials in the bucket 19 for eachunloading onto the conveyance vehicle 2, whereby the controller is ableto understand the loading amount onto the conveyance vehicle 2. Theloading amount onto the conveyance vehicle 2 is zero at the time of thefirst digging.

FIG. 22 is a diagram illustrating an example of a cross section of acurrent topography T1 and the digging path PA1. As illustrated in FIG.22, the controller 27 determines the digging path PA1 so that the volumebetween the surface of the current topography T1 and the digging pathPA1 (hatched portion in FIG. 22) matches the target volume. The diggingpath PA1 includes a digging start point S1 and a digging end point E1.The digging start point S1 and the digging end point E1 areintersections between the surface of the topography T1 and the diggingpath PA1. For example, the digging start point S1 is positioned furtheraway from the work machine 1 than the digging end point E1. Thecontroller 27 calculates the position of the digging start point S1 anddetermines the target rotation angle TA1 from the digging start pointS1. The controller 27 determines the target volume according to thepossible loading weight. The controller 27 calculates the specificgravity of the materials as described later and converts the possibleloading weight to a volume based on the specific gravity. The controller27 calculates a possible loading capacity from the possible loadingweight and calculates the target volume based on the possible loadingcapacity.

Specifically, when the possible loading capacity is equal to or greaterthan the digging capacity of the bucket 19, the controller 27 determinesthe digging capacity of the bucket 19 as the target volume. The diggingcapacity of the bucket 19 is stored in the storage device 272. When thepossible loading capacity is less than the digging capacity of thebucket 19, the controller 27 determines the possible loading capacity asthe target volume. The specific gravity or the target volume may be apredetermined initial value when the digging is executed the first time.

In step S206, the controller 27 executes an automatic down rotation.Here, as illustrated in FIG. 14, the controller 27 causes the rotatingbody 13 to rotate from the position in the waiting attitude forunloading toward the digging start point S1 by the target rotation angleTA1, and causes the blade tip of the work implement 12 to be loweredfrom the height in the waiting attitude for unloading toward the heightof the digging start point S1.

In step S207, the controller 27 executes automatic digging. Here, thecontroller 27 controls the work implement 12 so that the blade tip ofthe work implement 12 moves along the digging path PA1 determined in thedigging plan.

In step S208, the controller 27 modifies the position data of the workmachine 1. Here, the controller 27 reacquires the position data of thework machine 1, the attitude data of the work implement 12, and therotation angle data from the position sensor 33, the work implementsensors 34 a to 34 c, and the rotation angle sensor 39, respectively,and modifies the position of the work machine 1 acquired in step S102.

In step S209, the controller 27 establishes an unloading plan. Here, thecontroller 27 determines a target rotation angle TA2 and an unloadingposition P1 from the current position of the work machine 1 and the bedposition of the conveyance vehicle 2. The unloading position P1indicates the position of the blade tip of the bucket 19 in the waitingattitude for unloading. The bed position of the conveyance vehicle 2indicates the position of the bed 53 while the conveyance vehicle 2 ispositioned at the loading position L2. The controller 27 may store apredetermined bed position. Alternatively, the controller 27 maycalculate the bed position from the loading position L2 and the vehicledimension data of the conveyance vehicle 2. The controller 27 determinesthe unloading position P1 so that the work implement 12 faces toward thebed 53 and the blade tip is positioned a predetermined distance abovethe bed 53.

In step S210, the controller 27 executes an automatic hoist rotation.Here, as illustrated in FIG. 15, the controller 27 causes the rotatingbody 13 to rotate toward the unloading position P1 by the targetrotation angle TA2, and causes the blade tip of the work implement 12 tobe raised toward the unloading position P1.

In step S211, the controller 27 measures the weight of the materials dugby the work implement 12 and held by the bucket 19. Here, the controller27 acquires load data indicative of the load applied to the workimplement 12. The controller 27 calculates the weight of the materialsbased on the load data.

Further, the controller 27 calculates the specific gravity of thematerials from the topography data before digging, the digging path PA1,and the load data. The digging path PA1 corresponds to the topographyafter digging. Therefore, the controller 27 calculates the volume of thematerials dug by the work implement 12 from the topography data beforedigging and the digging path PAL. The controller 27 calculates thespecific gravity of the materials from the volume of the materials andthe weight of the materials calculated from the load data.

In step S301 illustrated in FIG. 8, the controller 27 determines a stateof the work machine 1. Here, the controller 27 determines whether thework machine 1 is operating or stopped. The controller 27 determinesthat the work machine 1 is operating when at least one of the travelingbody 14, the rotating body 13, and the work implement 12 is operating.The controller 27 determines that the work machine 1 is stopped when theblade tip of the work implement 12 reaches the unloading position P1 andall the traveling body 14, the rotating body 13, and the work implement12 are stopped. Alternatively, the controller 27 may determine that thework machine 1 is stopped when the rotating body 13 and the travelingbody 14 are stopped.

When the work machine 1 is stopped, the controller 27 executes imageprocessing 3 in step S302. In the image processing 3, the controller 27detects the conveyance vehicle 2 with image recognition technology basedon the first image data. In addition, the controller 27 communicateswith the conveyance vehicle 2 in step S303. Here, the controller 27receives the position data, the bed data, and the rotation angle data ofthe conveyance vehicle 2 via the communication device 38 in the same wayas in step S107.

In step S304, the controller 27 then determines a state of theconveyance vehicle 2. Here, the controller 27 determines whether theconveyance vehicle 2 is operating or stopped at the loading position L2.The controller 27 determines that the conveyance vehicle 2 is operatingwhen the conveyance vehicle 2 is traveling or when the bed 53 isrotating. The controller 27 determines that the conveyance vehicle 2 isstopped when the conveyance vehicle 2 is stopped at the loading positionL2 as illustrated in FIG. 16 and the bed 53 is not rotating and isstopped.

When the work machine 1 is stopped in step S301, the controller 27determines a state of the conveyance vehicle 2 based on the imageprocessing 3 and the position data of the conveyance vehicle 2 in stepS304. Therefore, the first camera 36 and the position sensor 33correspond to a detection device that detects the operation of theconveyance vehicle 2. The controller 27 determines whether theconveyance vehicle 2 is stopped based on the first image data. Further,the controller 27 determines whether the conveyance vehicle 2 is stoppedbased on the position data of the conveyance vehicle 2. That is, thefirst image data and the position data of the conveyance vehicle 2correspond to operation data indicative of the operation of theconveyance vehicle 2.

For example, the controller 27 may determine that the conveyance vehicle2 is stopped when the stop of the conveyance vehicle 2 is detected basedon both the image processing 3 and the position data of the conveyancevehicle 2. The controller 27 may determine that the conveyance vehicle 2is operating when the operation of the conveyance vehicle 2 is detectedbased on at least one of the image processing 3 and the position data ofthe conveyance vehicle 2.

When the work machine 1 is operating in step S301, the controller 27acquires the position data of the conveyance vehicle 2 in step S305, anddetermines a state of the conveyance vehicle 2 based on only theposition data of the conveyance vehicle 2 in step 304.

When the conveyance vehicle 2 is operating in step 304, the processingreturns to step S301. When the conveyance vehicle 2 is stopped in step304, the processing proceeds to step S306. In step S306, the controller27 executes image processing 4. In the image processing 4, thecontroller 27 detects the bed position of the conveyance vehicle 2 withimage recognition technology based on the first image data.

FIG. 23 is a view illustrating an example of an image captured by thefirst camera 36 when the conveyance vehicle 2 is stopped at the loadingposition L2. As illustrated in FIG. 23, the image indicated by the firstimage data includes the bed 53 of the conveyance vehicle 2. When the bed53 is included in the image indicated by the first image data, thecontroller 27 recognizes the bed 53 in the image and detects the bedposition.

In step S307, the controller 27 determines an error of the bed position.The controller 27 calculates a deviation between the bed position storedby the controller 27 and the bed position detected in step S306. Thecontroller 27 determines that the error is large when the deviation isequal to or greater than a predetermined threshold. When the error ofthe bed position is large, the processing proceeds to step S308.

In step S308, the controller 27 modifies the unloading position P1.Here, the controller 27 modifies the unloading position P1 determined instep S209 based on the deviation calculated in step S307. When the errorof the bed position is small in step S307, the unloading position P1 isnot modified and the processing proceeds to step S309.

In step S309, the controller 27 executes automatic unloading. Here, thecontroller 27 operates the work implement 12 so as to unload thematerials held by the bucket 19 onto the bed 53. In step S310, thecontroller 27 updates the bed position. The controller 27 updates thestored bed position to the bed position detected in step S306.

In step S401 illustrated in FIG. 9, the controller 27 determines whetherthe loading is finished. The controller 27 determines that the loadingis finished when the weight of the materials loaded onto the bed 53(hereinafter, referred to as “loading amount”) reaches the allowableweight. The controller 27 calculates the loading amount from the loaddata. Specifically, the controller 27 calculates the weight of the dugmaterials from the load data. The controller 27 calculates the totalvalue of the weight of the materials loaded onto the bed 53 as theloading amount. When the controller 27 determines that the loading isnot finished in step S401, the processing returns to step S201. Theprocessing from step S201 to step S211 and the processing from step S301to step S310 is repeated. Consequently, the material digging and loadingonto the conveyance vehicle 2 are repeated.

Even when the second and subsequent digging are performed, thecontroller 27 performs again the measurement of the topography performedin step S201 and updates the topography data with new topography dataacquired by the topography sensor 35. In addition, the controller 27performs again the measurement of the weight of the materials in stepS211, and calculates and updates the specific gravity of the materialsfrom the newly measured weight and volume of the materials.

In step S401, when the controller 27 determines that the loading isfinished, the processing proceeds to step S402. In step S402, asillustrated in FIG. 17, the controller 27 transmits, to the conveyancevehicle 2, a withdraw command to withdraw from the loading position L2.Upon receiving the withdraw command, the conveyance vehicle 2 startsmoving from the loading position L2 toward the dumping position L3.

In step S403, the controller 27 executes the image processing 2. In theimage processing 2, the controller 27 detects the presence of theconveyance vehicle 2 in front of the rotating body 13 with imagerecognition technology based on the first image data in the same way asin step S106. Further, in step S404, the controller 27 communicates withthe conveyance vehicle 2 and acquires the position data of theconveyance vehicle 2. Here, the controller 27 receives the position dataof the conveyance vehicle 2 via the communication device 38 in the sameway as in step S303 and step S305.

Next, in step S405, the controller 27 determines whether the withdrawalis completed. The controller 27 determines whether the withdrawal iscompleted based on the image processing 2 and the position data of theconveyance vehicle 2. As illustrated in FIG. 18, the controller 27determines that the withdrawal is completed when it is detected that theconveyance vehicle 2 has moved away from the work machine 1 by apredetermined distance or greater.

For example, the controller 27 calculates the distance between the workmachine 1 and the conveyance vehicle 2 based on the first image data.The controller 27 calculates the distance between the work machine 1 andthe conveyance vehicle 2 based on the position data. The controller 27may determine that the conveyance vehicle 2 has withdrawn from theloading position L2 when both the distance calculated from the firstimage data and the distance calculated from the position data are equalto or greater than a predetermined threshold. Alternatively, thecontroller 27 may determine that the conveyance vehicle 2 has withdrawnfrom the loading position L2 when at least one of the distancecalculated from the first image data and the distance calculated fromthe position data is equal to or greater than a predetermined threshold.

When the controller 27 determines that the withdrawal is not completedin step S405, the processing returns to step S403. When the controller27 determines that the withdrawal is completed in step S405, theprocessing returns to step S109. That is, when the controller 27determines that the withdrawal is completed, the controller 27 finishesthe loading mode and causes the automatic control mode to transition tothe standby mode.

With the control system of the work machine 1 according to the presentembodiment explained above, the controller 27 causes the automaticcontrol mode to transition from the standby mode to the loading modewhen the approach of the conveyance vehicle 2 has been detected.Accordingly, work can be performed by suitably coordinating the workmachine 1 and the conveyance vehicle 2. Consequently, the loading workby the work machine 1 is performed with the automatic control and workefficiency can be improved.

The controller 27 determines the digging path PA1 based on thetopography data indicative of the topography measured by the topographysensor 35, and controls the work machine 1 in accordance with thedigging path PA1. Consequently, the digging can be done with greaterprecision and efficiency.

The controller 27 acquires, from the first camera 36, the first imagedata in the forward direction of the work machine 1, and detects theapproach of the conveyance vehicle 2 based on the first image data. As aresult, the approach of the conveyance vehicle 2 can be detected withgood accuracy. In addition, the controller 27 also uses the positiondata of the conveyance vehicle 2 to detect the approach of theconveyance vehicle 2. As a result, the approach of the conveyancevehicle 2 can be detected with even greater accuracy.

Although an embodiment of the present invention has been described sofar, the present invention is not limited to the above embodiment andvarious modifications may be made within the scope of the invention.

The work machine 1 is not limited to a hydraulic excavator and may beanother machine such as a wheel loader, a motor grader, or the like. Theconfiguration of the work machine 1 is not limited to that of the aboveembodiment and may be changed. The work machine 1 may be a vehicledriven by an electric motor. For example, the traveling body 14 and/orthe rotating body 13 may be driven by an electric motor. Theconfiguration of the work implement 12 may be changed. For example, thework implement 12 is not limited to the bucket 19 and may includeanother attachment such as a grapple, a fork, a lifting magnet, or thelike.

The conveyance vehicle 2 may be a vehicle other than a dump truck. Theconfiguration of the conveyance vehicle 2 is not limited to that of theabove embodiment and may be changed. For example, the conveyance vehicle2 may be a vehicle driven by an electric motor. For example, thetraveling body 52 and/or the bed 53 may be driven by an electric motor.The bed 53 of the conveyance vehicle 2 may not be rotatable. Thetraveling body 52 of the conveyance vehicle 2 may be provided with tiresinstead of crawler belts. The conveyance vehicle 2 may not be underautomatic control and may be manually driven by an operator.

The configurations of the sensors provided on the work machine 1 and theconveyance vehicle 2 are not limited to those of the above embodimentand may be changed. For example, the topography sensor 35 may bedisposed in a part other than the side part of the rotating body 13. Thetopography sensor 35 is not limited to a LIDAR device and may be anothersensing device such as a radar device or the like. Alternatively, thetopography sensor 35 may be a camera and the controller 27 may recognizethe topography by analyzing the images captured by the camera.

The first camera 36 may be disposed in a part other than the front partof the rotating body 13. The second cameras 37 may be disposed in partsother than both side parts and the rear part of the rotating body 13.The number of the second cameras is not limited to three and may be lessthan three or greater than three.

The controller 27 is not limited to one unit and may be divided into aplurality of controllers 27. The processing executed by the controller27 may be distributed and executed among the plurality of controllers27. In such a case, a portion of the plurality of controllers 27 may bedisposed outside the work machine 1.

The controller 27 of the work machine 1 and the controller 61 of theconveyance vehicle 2 may not communicate with each other directly, andmay communicate through another controller. The processing in theautomatic control mode executed by the controller 27 is not limited tothat of the above embodiment and may be changed. For example, theprocessing in the standby mode may be changed. The processing in theloading mode may be changed.

In the above embodiment, the controller 27 uses both the first imagedata and the position data of the conveyance vehicle 2 to determine theapproach and the withdrawal of the conveyance vehicle 2. However, thecontroller 27 may use only one of the first image data and the positiondata of the conveyance vehicle 2 to determine the approach and/or thewithdrawal of the conveyance vehicle 2.

In the above embodiment, the controller 27 uses both the first imagedata and the position data of the conveyance vehicle 2 to detect theposition of the bed 53. However, the controller 27 may use only one ofthe first image data and the position data of the conveyance vehicle 2to detect the position of the bed 53.

In the above embodiment, the controller 27 calculates the possibleloading weight based on the load data detected by the load sensors 32 ato 32 c. However, the controller 27 may calculate the possible loadingweight based on the image of the bed 53 indicated by the first imagedata. The controller 27 may detect the amount of the materials loadedonto the bed 53 from the image of the bed 53 indicated by the firstimage data to calculate the possible loading weight from the amount ofthe loaded materials.

According to the present invention, it is possible to perform loadingwork by the work machine with automatic control and improve workefficiency.

1. A system for controlling a work machine that loads materials onto aconveyance vehicle, the system comprising: a controller configured tocontrol the work machine in an automatic control mode in which work isperformed automatically; and a detection device configured to detect anapproach of the conveyance vehicle toward the work machine, theautomatic control mode including a loading mode in which the workmachine is caused to move to perform loading work for loading onto theconveyance vehicle, and an other mode other than the loading mode, theother mode including at least one of a mode for gathering fallenmaterials and a digging mode for further increasing the materials bydigging, and the controller being configured to cause the automaticcontrol mode to transition from the other mode to the loading mode whenthe approach of the conveyance vehicle is detected.
 2. The systemaccording to claim 1, wherein the work machine includes a workimplement, and a rotating body to which the work implement is attached,and the controller is further configured to control the work implementand the rotating body in the loading mode.
 3. The system according toclaim 2, wherein the work machine further includes a topography sensorconfigured to measure a topography, and the controller is furtherconfigured to acquire topography data indicative of the topographymeasured by the topography sensor, and control the work implement andthe rotating body based on the topography data in the loading mode. 4.The system according to claim 3, wherein the controller is furtherconfigured to determine, in the loading mode, a digging start positionbased on the topography measured by the topography sensor.
 5. The systemaccording to claim 4, wherein the controller is further configured tocontrol the rotating body to rotate based on the digging start positionin the loading mode.
 6. The system according to claim 2, wherein thecontroller is further configured to maintain at least the work implementat a stopped state in the other mode.
 7. The system according to claim1, wherein the detection device includes a camera that captures aperiphery of the work machine, and the controller is further configuredto acquire image data indicative of an image of the periphery of thework machine captured by the camera, and detect the approach of theconveyance vehicle based on the image data.
 8. The system according toclaim 1, wherein the conveyance vehicle includes a position sensor thatdetects a position of the conveyance vehicle, the detection deviceacquires position data indicative of the position of the conveyancevehicle detected by the position sensor, and the controller is furtherconfigured to detect the approach of the conveyance vehicle based on theposition data.
 9. The system according to claim 1, wherein thecontroller is further configured to cause the automatic control mode totransition from the loading mode to the other mode when withdrawal ofthe conveyance vehicle is detected.
 10. The method according to claim 1,wherein the other mode further includes a standby mode.
 11. A method forcontrolling a work machine that loads materials onto a conveyancevehicle, the method comprising: detecting an approach of the conveyancevehicle toward the work machine; and controlling the work machine in anautomatic control mode in which work is performed automatically, theautomatic control mode including a loading mode in which the workmachine is caused to move to perform loading work for loading onto theconveyance vehicle, and an other mode other than the loading mode, theother mode including at least one of a mode for gathering fallenmaterials and a digging mode for further increasing the materials bydigging, and the controlling the work machine including causing theautomatic control mode to transition from the other mode to the loadingmode when the approach of the conveyance vehicle is detected. 12.(canceled)
 13. The method according to claim 11, wherein the workmachine includes a work implement, and a rotating body to which the workimplement is attached, the method further comprises acquiring topographydata indicative of a topography, and the controlling the work machineincludes, in the loading mode, controlling the work implement and therotating body based on the topography data.
 14. The method according toclaim 13, further comprising: determining, in the loading mode, adigging start position based on the topography indicated in thetopography data.
 15. The method according to claim 14, wherein thecontrolling the work machine further includes controlling the rotatingbody to rotate based on the digging start position in the loading mode.